As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
EMERGENCY LIGHTS DID NOT ILLUMINATE WHEN POWER ON CHECKLIST WAS BEING COMPLETED. PERFORMED AN OPS CHECK OF THE EMERGENCY LIGHTING SYSTEM PER AMM 33-50-00-710 AND DETERMINED #4 ERNER LIGHTING BATTERY CHARGER TO BE DEFECTIVE. REMOVED AND REPLACED #4 ERNER LIGHTING BATTERY CHARGER WITH A REPAIRED UNIT PER AMM 33-50-06 AND OPS CHECKED GOOD.